The present invention relates to the field of maintenance and repair sequences for complicated equipment. More particularly, the present invention relates to apparatus and method for guiding human operators through a sequence of tasks such as removing of paper jams in complex production reprographic equipment. While this invention will be illustrated in relation to the task of removing such paper jams, it is believed that the apparatus and methods of the present invention have wide applicability, particularly to routine maintenance or repair operations to be performed by human operators that have not been specially trained and for such operations when many variables combine to vary the sequence from one operation to the next.
Although the art of avoiding paper jams has progressed steadily since reprographic printing systems were commercialized, paper jams remain an unfortunate occasional occurrence. Much work has occurred in preventing, diagnosing, and ameliorating the effects of paper jams. For instance, it has become common for printing systems to include a series of sensors designed to detect the location where a paper jam occurs. Since, as will be explained more thoroughly below, many sheets are typically being processed within a large printer simultaneously, some sheets will usually have progressed in the paper path beyond the point of the jam while others will have left the input copy paper bin but not yet have been processed by the system up to the point of the jammed sheet. In U.S. Pat. No. 4,627,711 issued to Schron and U.S. Pat. No. 4,497,569 issued to Booth, a controller for the print system detects the existence of a paper jam and its location. The controller then deduces which sheets in the system may continued to be processed through completion and which need to be halted in situ because of interference by the jam. Such commands are then given, and some sheets within the body of the printer are processed to completion while others remain stationary within the printer. Also, typically, in such systems and in other modern printers with recirculating feeders, the controller analyzes the condition of sheets halted by paper jams and, after the jams have been cleared, directs the operator through the user Interface (UI) to reassemble the sheets to be copied in a specified order in order to resume printing or copying of the job. An operator may also cancel the jammed job and reassemble the sheets in any order the operator prefers in order to complete the job.
All of these features of modern reprographic systems indicate the high degree of control and sophistication now enabled by microprocessors and sensors operating in conjunction with sophisticated control algorithms. These features also indicate that different types of paper jams occurring in different locations require different solutions. For an operator, this often means that different parts of a machine must be opened, and sheets in different locations and orientations must be removed. In many machines, the UI instructs the operator which cabinet doors must be opened and/or components like finishers must be separated. In relatively simple printing systems, an operator that opens a cabinet as instructed for a paper jam can easily observe various levers and handles which need to be moved in order to observe or reach jammed or halted sheets in the printer. In many printers such as those designed and marketed by Xerox Corporation, these doors and handles are colored a unique pale green and are often numbered. The purpose of the numbering system is to guide the operator through the various steps required to access all portions of the paper path within the relevant cabinet.
Higher speed printing systems are often more complex and usually contain longer paper paths. Since, as described above, different portions of a sheet path may be automatically cleared depending upon where the paper jam occurred, different portions of a complex printing machine may need to be opened. Further, the order in which different subassemblies should be opened often differs depending upon the location and type of paper jam. Lastly, in some complex systems, simple numbering of handles and levers is not sufficient to guide operators since the disassembly and reassembly of various components requires varying and complex operations. For instance, where subassemblies such as development apparatus are located on trays that can be accessed best after being slid out from the cabinet, it is important that trays that have been so moved be pushed entirely back into their proper location and secured in place before other components such as baffles and conveyance rollers are pressed back into position in contact with such removable tray.
For such complex systems requiring various sequences of operations depending upon the paper jam or other fault to be fixed and, further, requiring confirmation that particular steps in an operation be completed before subsequent steps are performed, its has become routine for operators to rely upon information displayed in the UI or other human interface to determine whether assembly or disassembly operations have been properly completed and, if so, which operations are to be performed next in the sequence. This often requires that an operator move back and forth between the UI and the cabinet or work space where the operations must be performed. The larger and more complex the equipment, the more important guidance from sensors within the system and cooperating control algorithms becomes. Also, the less trained the operators, the more reliant upon such instructions in a UI the operator becomes. For an equipment manufacturer, it is desired that machines be as easy to maintain as possible by customers in order to avoid service calls and to require as little operator time and training as possible.
Accordingly, it would be advantageous to have an apparatus and process that automatically guides an operator through various sequences for maintenance and repair without the need to continually refer to repair manuals or to human interfaces such as a systems UI. Such an automatic guide system would preferably allow an operator to remain in situ at the place of repair, maintenance or reassembly without needing to physically move or to change the focus of his/her attention. With such an automatic guide system, repair, maintenance, and assembly/reassembly processes should become more efficient and more reliable with decreased risk that an improper sequence will damage components, and require less training for human operators. A further advantage is that the present invention not only may be adapted to guide the sequence of operations but may, in addition, be adapted to direct movements or other manipulation of levers, latches, pulls, knobs, drawers, etc.
An apparatus requiring an operator to perform mechanical procedures upon the apparatus, such apparatus having parameters indicating apparatus status including fault parameters and nominal parameters, comprising: a controller for determining the sequence of procedures; a first human interpretable indicator, in communication with the controller and located proximate to an apparatus site where a procedure is to be performed; a second human interpretable indicator, in communication with the controller and located proximate to an apparatus site where a procedure is to be performed; a first sensor, associated with a first human interpretable indicator, for sensing an apparatus status parameter at the site proximate to the first human interpretable indicator, said first sensor communicating such parameter status to the controller; a second sensor, associated with a second human interpretable indicator, for sensing an apparatus status parameter at the site proximate to the second human interpretable indicator and for communicating such status to the controller; and a control algorithm used by the controller that, in response to a signal from the first sensor that a fault parameter exists, directs the controller to activate the first human interpretable indicator and, in response to a signal from the first sensor that a nominal parameter exists, inquiries the second sensor whether a fault parameter exists and, if such fault parameter exists, directs the controller to activate the second human interpretable indicator.